Portable power bank



FIG. 1 is a top view of a portable power bank, showing my new design, the bottom side being a mirror image thereof;

FIG. 2 is a front view thereof, the rear being a mirror image thereof;

FIG. 3 is a left side view thereof;

FIG. 4 is a right side view thereof;

FIG. 5 is a top left perspective view thereof; and,

FIG. 6 is a top right perspective view thereof. 

CLAIM The ornamental design for a portable power bank, as shown and described. 